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Montoya Tena G.,Electric Research Institute of Mexico | Hernandez C. R.,Electric Research Institute of Mexico | Montoya T. J.I.,Polytechnic University of the Valley of Mexico
Electric Power Systems Research | Year: 2010

The bird excrement, combined with humidity, causes line outages in transmission lines. In order to standardize the criteria to solve the problem, a research project was developed in México. The solutions found in worldwide review can be classified into four groups: elimination of birds, devices of dissuasion, physical barriers, and covering devices. The first group includes all bird elimination techniques. These alternatives are forbidden in México, and in most of the countries. The second group has shown to be effective at the beginning of its application; however once the birds are habituated to the device, it loses its effectiveness. The efficiency of the third group, the use of physical barriers, is high, as demonstrated by more than a few review reports informing drastic reductions of flashovers on the transmission lines where they have been installed. The fourth group is conformed by components whose function is to protect or to cover the insulation. According to the experience in Mexico, covering devices have shown to be very effective. The contamination by bird excrement has not a unique solution. The most viable solution is a combination of alternatives. Even though, a solution adopted for a region may not be suitable for another region. Therefore, each case should be approached according to the particular conditions of the region. © 2009 Elsevier B.V. All rights reserved.

Sharma H.,Indian Institute of Technology Ropar | Guadalupe H.J.,National Autonomous University of Mexico | Narayanan J.,Polytechnic University of the Valley of Mexico | Hofeld H.,Autonomous University of the State of Morelos | And 2 more authors.
Analytical Methods | Year: 2013

Three ruthenium(ii) and (iii) metal complexes of the compositions ([Ru(1)(Cl)(PPh3)]+ (4), ([Ru(2)(Cl)(PPh 3)]+ (5) and ([Ru(3)(Cl)(H2O)]2+ (6) have been synthesized from oligodentate pyridyl-(1) and benzimidazole ligands (2-3) and structurally characterized. Our investigations revealed that if the coordination sphere of the metal ion carries a strong coordinating PPh 3 ligand (complexes 4 and 5), the framework was not suitable for anion binding at all. However, when coordination of solvent (H2O) to the metal centre occurred instead (complex 6), a receptor for anion recognition through fluorescence spectroscopy could be generated. This allowed us to develop a sensor for the selective recognition of chloride over several other anions. In order to screen potential applications, the sensor was tested for the determination of chloride concentration in a series of four commercially available oral rehydration salts, giving excellent agreement with the values reported by the corresponding manufacturer. The detection limit was established to be 5 μM. © 2013 The Royal Society of Chemistry.

Gonzalez Rodriguez C.A.,Polytechnic University of the Valley of Mexico | Galicia Aguilar G.,National Autonomous University of Mexico | Velazquez Sanchez A.T.,Polytechnic University of the Valley of Mexico | Cruz Mejia H.,Polytechnic University of the Valley of Mexico
ECS Transactions | Year: 2013

In this work the degree of sensitization of several samples of austenitic stainless steel 304 sensitized at 600 and 700 °C during 1h, was determined by Local Electrochemical Impedance Spectroscopy. The experimental methodology consisted of several steps. Firstly, a chemical analysis of each sample was realized by spark emission spectroscopy, after a metallographic characterization was done and finally tests of double loopelectrochemical potentiodynamic reactivation (DLERP) were applied in each sample. Additionally, carbides precipitation in the border grain was observed using a Scanning Electron Microscopy (SEM). The spectra of local impedance were realized into austenitic grain, the results obtained showed a capacitive behavior. On the other hand in the grains limits (where chromium carbides are formed), a resistive - capacitive behavior is observed. This difference indicates what zone is most susceptible to intergranular corrosion (CIG), whereas DLEPR is unable to discern any evidence about this. © The Electrochemical Society.

Camacho R.-L.,Autonomous University of the State of Hidalgo | Montiel E.,Autonomous University of the State of Hidalgo | Jayanthi N.,Polytechnic University of the Valley of Mexico | Pandiyan T.,National Autonomous University of Mexico | Cruz J.,Autonomous University of the State of Hidalgo
Chemical Physics Letters | Year: 2010

The adsorption capability of α-diimines N-ethylamine-1,2-dimethyl-α-diimine, N-ethylhydroxy-1,2-dimethyl-α-diimine and N-ethylthiol-1,2-dimethyl-α-diimine over iron-clusters was studied by DFT. The results show that since these compounds possess suitable structural and electronic parameters for metal adhesion, α-diimines strongly adsorb over the metal clusters. Moreover, the calculated binding energy supports the existence of a bond between α-diimine and the iron metal, consisting of the transfer of high-charge density which in the delocalization region (N1{double bond, long}C2-C3{double bond, long}N4) is formed by p (nitrogen) and π (C{double bond, long}N) to the metal (L(σ) → Fe). Furthermore, the binding nature of the compounds with the metal is then confirmed in molecular orbital studies by detecting the overlap of HOMO (diimines) with LUMO (iron). © 2009 Elsevier B.V. All rights reserved.

Guadalupe H.J.,National Autonomous University of Mexico | Narayanan J.,Polytechnic University of the Valley of Mexico | Pandiyan T.,National Autonomous University of Mexico
Journal of Molecular Structure | Year: 2011

Ruthenium complex of N,N′-bis(benzimidazol-2-yl-ethyl)ethylenediamine (L1) was prepared and characterized by analytical methods. Structural and spectral properties of N,N′-bis(benzimidazol-2-yl-ethyl) ethylenediamine (L1), its dianionic structure (L2), and their complexes such as [RuL1Cl(PPh3)]+ and [RuL2Cl(PPh3)]+ were studied by DFT. In the structures, the ruthenium ion is positioned in an equatorial plane formed by amine, benzimidazole nitrogens in a distorted octahedral geometry, and chloride and triphenylphospine are axially coordinated. Furthermore, the molecular orbital of [Ru(L)Cl(PPh3)]Cl (L = L1 or L2) proves that the HOMOs are localized over the benzimidazole and amine moieties, favoring a strong bond with the metal. DFT-TDDFT was used to analyze the molecular orbitals contribution to MLCT bands that were observed in the visible region; interestingly, the calculated spectrum of [RuL1Cl(PPh 3)]+ qualitatively agrees only with high energy bands (465 nm and 350 nm) of the experimental spectrum, and other visible bands (≈580 and ≈790 nm) observed in the experimental spectrum coincide with the TD-DFT of [RuL2(PPh3)Cl]+. However, electrochemical studies show existence of only [RuL1Cl(PPh3)]+ in the solution. © 2011 Elsevier B.V. All rights reserved.

Gomez M.A.,CINVESTAV | Ochoa G.,Polytechnic University of the Valley of Mexico | Mondie S.,CINVESTAV
International Journal of Robust and Nonlinear Control | Year: 2016

Exponential stability necessary conditions for linear periodic time-delay systems are presented. They are obtained with the help of new properties of the Lyapunov matrix in the framework of Lyapunov-Krasvoskii functionals of complete type. An academic example illustrates our results. © 2016 John Wiley & Sons, Ltd.

Trujano M.A.,Polytechnic University of the Valley of Mexico | Garrido R.,CINVESTAV
ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) | Year: 2013

This work presents an image-based visual servoing scheme applied to planar parallel robots. A PID algorithm regulates the robot end-effector position, and rejects constant disturbances perturbing the active robot joints. Instead using the La Salle invariance theorem, the stability analysis provided here relies on a strict Lyapunov function. Experiments on a redundant planar parallel robot validate the proposed control scheme. Copyright © 2013 by ASME.

Cuvas C.,CINVESTAV | Mondie S.,CINVESTAV | Ochoa G.,Polytechnic University of the Valley of Mexico
IFAC Proceedings Volumes (IFAC-PapersOnline) | Year: 2015

The paper presents necessary stability conditions for distributed delay systems with truncated Gamma distribution. Motivated by the known Lyapunov equation for delay free linear systems, these conditions depend only on the Lyapunov delay matrix of the system. In conjunction with the D-subdivision boundaries, the necessary conditions are employed to find instability regions in the space of parameters of the system. The result is illustrated by an example. © 2015, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

Alvarez I.,Polytechnic University of the Valley of Mexico | Poznyak A.,CINVESTAV
ICCAS 2010 - International Conference on Control, Automation and Systems | Year: 2010

Traffic congestion is an issue in every major city. Among many approaches the game theory has presented feasible solutions. In this paper, a noncooperative approach which gives rise to a noncooperative game is studied, we propose to model signalized intersections as finite controlled Markov chains and a solution to optimize the congestion into an avenue. Each intersection is seen as noncooperative game where each player try to minimize its queue, so ∈-Nash's equilibrium and Stackelberbg equilibrium are the solutions. This paper is focused on the traffic light control problem for urban traffic, using Game Theory and Extraproximal Method for its realization. The examples show the effectiveness of the suggested approach. ©ICROS.

Lopez Perrusquia N.,National Polytechnic Institute of Mexico | Antonio Donu Ruiz M.,National Polytechnic Institute of Mexico | Vargas Oliva E.Y.,Polytechnic University of the Valley of Mexico | Cortez Suarez V.,Metropolitan Autonomous University
Materials Research Society Symposium Proceedings | Year: 2013

This work estimate the growth kinetics of Fe2B coatings created on surface nodular cast iron ASTM A-536 class 80-56-06. The Fe2B coatings were formed by power packaging boriding process, considering three temperatures and exposure times different treatment. The hard coatings were evaluated through X-ray diffraction (XRD) and scanning electron microscopy (SEM). The model of diffusion employs the mass balance equation at the (Fe 2B/substrate) interface to evaluate the boron diffusion coefficient in the Fe2B coating DFe2B, an expression of the parabolic growth constant, the instantaneous velocity of the Fe2B/substrate interface, and the weight gain in the boriding sample were establish as a function of the parameter ε(T) and η(T), dependents of bonding process in function of the temperature related and the time of boriding t 0(T), respectively in the Fe2B coating. Model validation was extended considering the treatment of 1273 and 1123 K for 10 h respectively, obtaining a good correlation with experimental data. © 2012 Materials Research Society.

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